Base for non-solid writing media



United States Patent BASE FOR NON-SOLID WRITING MEDIA Gerald A.Goessling, Richmond Heights, M0.

N0 Drawing. Application May 10, 1954 Serial No. 428,787

3 Claims. (Cl. 106-31) The present invention relates generally towriting media, and more particularly to a novel base or vehicle fornon-solid writing media which are particularly adapted for use inrotating-ball type Writing instruments, and Whlch are controllable as totheir physical characteristics to provide an erasable non-smudgingwriting medium, a permanent non-smudging medium, or a non-smudgingwriting medium having erasability and penetrating characteristicsanywhere therebetween.

Briefly, the invention resides in a writing media base for pigments ordyes (or both), comprising an asphaltum or tarry mass, and predeterminedamounts'of a relatively light oil to control the erasability andpenetrability of the resultant writing medium.

During recent years, much effort has been directed toward developinginks for use in rotating-ball type instruments which are permanent,which will not transfer or smudge, and which will write on wet or oilsmudged paper. Efforts have also been made to develop inks whichproduced marks which simulate the marks produced by conventional leadpencils, and which are readily erasable. In short, the requirements asto erasability, permanency, and the like, vary with the particular userequired of the ink or writing medium. Although many inks and othertypes of non-solid writing media have been developed which satisfy someof these requirements, each has to be tailormade to meet a particularrequirement and is completely different in chemical composition andphysical make-up from one produced to satisfy different requirements.Also, most of the known inks have relatively short shelf life and tendto leak from the writing instrument when it is subjected to heat.

It is an object of the present invention, therefore, to provide a novelbase or vehicle for non-solid writing media which can be used with dyesor pigments, or both, and which can be controlled with respect to itsphysical characteristics to produce a writing medium which will notsmudge or transfer and which will be substantially permanent, or toproduce a readily erasable non-smudging writing medium, or to produce awriting medium having erasability or permanency characteristics anywheretherebetween. More particularly it is an object to provide such a baseor vehicle which can be used with various types of coloring matter andwhich can be readily controlled as to its physical composition duringthe manufacture of the writing medium, to produce a writing me diumwhich will quickly penetrate into the fibers of the paper so as to bepermanent and which will not transfer or smudge, or to produce a writingmedium which will have very little penetration into the paper so as tolie on the surface thereof and be readily erasable Another object is toprovide a base for writing media which will write on practically anytype of paper without globbing or skipping and which will not be ad-.versely affected by changes in paper surface characteristics, such as amoist surface or a slick or oil smudged surface. More particularly, itis an object to provide a base 2 for writing media for use inrotating-ball type writing instruments which will write on moist orslick or oil smudged paper without transferring and without spreading.

Another object is to provide a base for writing media which remainwithin the writing instrument until the latter is moved over the paperor the like, which do not bleed or leak from the instrument, and whichdo not cling to the exposed point of the writing instrument when it isnot in use.

Another object is to provide a base for writing media which do notharden or dry out on exposure to the air as when on the point of awriting instrument, and which have long shelf life.

Further objects and advantages will be readily apparent from thefollowing detailed description.

In order to perform satisfactorily in a rotating-ball type writinginstrument, the resultant writing medium must have sufficient body andcohesive strength to remain within the writing unit until it is rolledonto the writing surface. On the other hand, it cannot be too viscous orit will not flow freely through the writing instrument.

Furthermore, it should have sufficient cohesive strength with respect toitself (surface tension) whereby it will not crawl, slip or leak fromaround the ball or from the upper end of the writing unit, but will workdown toward the ball as the writing medium is consumed.

The cohesion or film strength must also be sutficient to cause themedium to flow or be pulled in a uniform unbroken film from thecapillary tube, around the ball and onto the writing paper.

The Writing medium must also have sufficient adhesive strength orafiinity for the ball to cling to it and be pulled from between the balland its seat, and onto the paper. However, its affinity for the writingpaper must be greater than its affinity for the ball so that it will bereadily transferred from the ball onto the paper and not pile-up on theperipheral edge of the ball seat.

Also, it is desirable for the medium to have more cohesive strength withrespect to itself than adhesive strength with respect to the surface ofthe ball, whereby it will contract or draw back into the space betweenthe ball and its seat, and provide a clean point.

I have developed a base or vehicle for producing nonsolid writing mediawhich have all of the foregoing desirable characteristics. This base canbe used with either oil-soluble dyes, colored pigments, or combinationsof dyes and pigments, and can be controlled by changing the relativeproportions of the principal ingredients whereby the resultant writingmedium will lie on the surface of the paper and be readily erasable, orwhich can be made to penetrate into the fibers of paper so as to bepermanent.

The desired base or vehicle which has been developed has the generalphysical characteristic which can best be described as viscid or tacky.One .method of producing this so-called base or vehicle is to dissolve atarry petroleum or bituminous material such as asphalt or tar in'apetroleum thinner'or light mineral oil and a solvent such as VMP(varnish makers and printers base) naphtha. After the asphalt or tar isdissolved, the naphtha is evaporated, as with heat, leaving the asphaltor tar dissolved vehicle) is in the nature of 4 to 1, i. e., when theasphaltic' content is about of the starting base. The dissolvedConsequently, best results are ob- 3 asphalt comprising about 16% to 32%by volume of the resultant writing composition as pointed out in my copending application Serial No. 399,221, filed December 21, 1953.

Satisfactory results are also obtained by using as the starting base,petroleum products distributed by various oil companies and which arebasically a distillate residue and oil. For example, Cities Service OilCompany markets such a product as Cisco No. 5, -No. SZ, or the like,depending upon the amount of oil mixed 'with the distillate residue.Cisco No. 5 is a residual petroleum asphaltic material which has anapproximate dropping point (ASTM degrees Fahrenheit) 143,-anunworked-cone penetration at 77 F. of approximately 245, and a viscosityof approximately 5,000 seconds SUS at 210 F. Cisco No. 5Z'is similar toNo. 5 except that it is diluted with trichloroethyleneto reduce itsviscosity.

The resultant base is produced by adding to the aforementioned startingbase, a predetermined amount of a highly refined oil, which controls thepenetration and erasibility characteristics of the resultant writingmedium.

The oil is preferably a mineral oil of the non-detergent type so as notto cause the resultant writing medium to transfer or spread when incontact with moisture, or even when used on wet paper.

Another disadvantage of using an oil which contains detergents, is thatthe detergents may cause a caking or drying out of the resultant writingmedium and adversely affect its shelf life. This is especially true whenthe coloring matter is an oil-soluble dye, as will be discussed morefully hereinafter.

A preferred oil is Rocket F oil, a highly refined parafiin base,non-detergent type mineral oil used in the printing industry and whichcan be obtained from Sinclair Refining Company, which is a subsidiary ofSinclair Oil Corporation. It is advisable to use high grade, highlyrefined oils primarily because they are produced under mfire strictcontrols and are more uniform than ordinary 01s.

A resultant base or vehicle which will produce a writing medium whichdoes not penetrate into the fibers of the paper, relatively speaking,and which is readily-erasable, is produced, for example, by using about90% to 95%, by volume, Cities Service Cisco No. SZ, and about 5% to byvolume, of Rocket F oil.

On the other hand, if it is desired to produce a writing medium whichpenetrates rapidly into the fibers of the paper, relatively speaking,and which does not smudge or transfer, more of the Rocket F oil is used,c. g. about 30% oil and about 70%-Cisco No. 5Z.

The amount and weight of oil which is used is also dependent upon thetype of materials used in the manufacture of the capillary tube and theball point, and also upon the staking space between the ball and itsseat.

The necessary coloring matter to produce the desired color, is thenadded to the resultant base or vehicle in order to complete the writingmedium. The coloring matter can be in the form of a pigment, anoil-soluble dye, or a combination of the two. In order to prevent theresultant writing medium from smudging or transferring, the coloringmatter should. be non-soluble with respect to water, and furthermore,the vehicle itself should be non-soluble, and the combination of thevehicle and the coloring matter should be non-soluble.

To provide a writing medium which produces marks which simulate themarks produced by conventional pencil leads and which are readily erasedin like manner, a colloidal dispersion of graphite and/ or carbonparticles in a light oil (SAE) having a paraflin base is used. All ofthe particles are substantially less than 7 microns in size andpreferably no more than about 3 to 4 microns.

When graphite particles are used, the best results are ob-.

tained when the particle content is between about 10% to by weight ofthe resultant writing medium and preferably between about 15% to 17%. Toobtain the 4 maximum concentration of graphite in the preferred finalweight range (15% to 17%) above pointed out, a dispersion of about 30%by weight of graphite particles in oil has been used. The colloidaldispersion is combined with the aforementioned erasable base in theproportions of about 20% to 40% by volume base to about 60% to by volumegraphite in oil. In like manner, coloring pigment such as organictoners, e. g. barium lithol, monastral blue, and the like, can be usedto produce writing media of various colors, and which are also readilyerasable. Erasable non-solid Writing media of this type are fullydescribed in my copending application Serial No. 399,221, filed December21, 1953.

Furthermore, to produce various colors, one can use oil-soluble dyeswhich are non-soluble with respect to Water and which are dissolved inalong chain fatty acid such as oleic acid, in the ratio of about 1020%solids and about 80-90% carrier (the fatty acid, in effect, taking theplace of the mineral oil as when colloidal graphite is used), such asfor example, Aviation Blue (Color Index No. 2182) or Oil Soluble Black(Color Index No. '864) of Calc'o ChemicalCo, or Amaplast Red B (ColorIndex No. 258), Amaplast Green BB (Color Index No. 1078), or AmaplastBlue RB (Color Index No. 1073) of American Aniline'Products, Inc., orJet Oil Black (Color Index No. 864) or Oil Blue (Color Index No. 2182)of General Dyestuif Corporation, or Jet Oil Black or Oil Blue 2182 ofGeneral Dyestutt' Corporation, 435 Hudson Street, New York 14, N. Y., adivision of General Aniline and Film Corporation, 230 Park Avenue, NewYork 17, N. Y., either alone or with pigments, and, by using varyingamounts of Rocket F oil,-colored writing media 'canbe produced whicheither lie on the surface'and-are readily erasable, or which penetrateinto the fibers of the paper so as to be permanent, and which do notsmudge or transfer.

While the graphite particle composition mentioned above will produce ablack marking and the colored pigment and/or oil soluble dye compositionmay be used to produce colored markings, the amount of the highlyrefined oil put into the composition will determine whether the writingcomposition Will penetrate the paper to which his applied and,therefore, not be erasable, or will not penetrate the paper and will beerasable therefrom.

Naturally, when coloring matter and the oil in which it is suspended ordissolved are added to the aforementioned resultant base or vehicle,this oilmust be considered in determining the total amount of oil whichshould be used in the resultant medium, depending upon whether it isdesired to produce an erasable medium or apenetrating medium.

Furthermore, it will be readily apparent that the type of paper on whichthe writing medium is used will, to some degree, affect the erasabilityand penetration of the writing medium. Thus, a resultant writing mediumis more apt topenetrate the fibers of a soft-finish paper such asnewspaper, than a hard-finish paper having a heavy starch coating.

Thus, it is apparent that there has been provided a re sultant base orvehicle for non-solid writingmedia, which fulfils all of the objects andadvantages sought therefor.

By beginning with the aforementioned starting base of dissolvedasphaltum or tar and by adding varying amounts of a light oil thereto,writing media can be produced which do not smudge or transfer, and whicheither lie on the surface of the paper and are readily erasable,

or which quickly penetrate into the fibers of the paper so as to bepermanent.

Also, the base can be used with colloidal pigments, with oil-solubledyes, or a combination of the two, to produce various colors or a blackwhich simulates the marks produced by conventional pencil leads.

. In addition, the resultant writing media which are produced followingthe teachings of the present invention, can be used to Write on wet andoil smudged surfaces and will not spread or smear.

and said tar-like Furthermore, the physical characteristics of the mediado not change on exposure to air, whereby the instrument is always readyto write and does not require any priming movement, and has long shelflife.

Consequently, there has been produced what is, or what closelyapproaches, a universal base for non-solid writing media having variableerasibility and penetrating characteristics, and which do not smudge ortransfer.

It is to be understood that the foregoing descriptions have been givenonly by way of illustration and example and that changes and alterationsin the present disclosure, which will be readily apparent to one skilledin the art, are contemplated as within the scope of the presentinvention, which is limited only by the claims which follow.

What is claimed is:

l. A writing composition which simulates the markings of a conventionalpencil lead consisting essentially of a stable colloidal dispersion ofgraphite particles in a light petroleum oil with substantially all ofthe graphite particles being less than 7 microns in size as the pigmentand said graphite particles being from 10% to 25% by weight of thewriting composition, a carrier comprising a tar-like substance selectedfrom the group consisting of tar derived from petroleum and bituminousdistillate residue and asphalt dissolved in a petroleum thinner and oil,said colloidal dispersion being from 60% to 80% by volume of the writingcomposition and said carrier being from 20% to 40% by volume of saidwriting composition substance being from about 16% to 32% by volume ofsaid writing composition, and adding to said composition from about 5%to 30% by volume of a refined paraffin base non-detergent typemineral'oil whereby the writing composition can be controlled betweenone which remains substantially on the surface and is relativelyerasable and one which penetrates the surface and is relativelyunerasable.

2. The writing composition as set forth in claim 1 wherein about 5% to10% by volume of the refined paraffin base oil is added to the saidcomposition whereby the writing composition will remain substantially onthe surface and be erasable.

3. The writing composition as set forth in claim 1 wherein about 30% byvolume of the refined paraffin base oil is added to the writingcomposition whereby the writing composition will penetrate the surfaceto which it is applied and will be unerasable therefrom.

References Cited in the file of this patent UNITED STATES PATENTS GreatBritain of 1881

1. A WRITING COMPOSITION WHICH SIMULATES THE MARKINGS OF A CONVENTIONALPENCIL LEAD CONSISTING ESSENTIALLY OF A STABLE COLLOIDAL DISPERSION OFGRAPHITE PARTICLES IN A LIGHT PETROLEUM OIL WITH SUBSTANTIALLY ALL OFTHE GRAPHITE PARTICLES BEING LESS THAN 7 MICRONS IN SIZE AS THE PIGMENTAND SAID GRAPHITE PARTICLES BEING FROM 10% TO 25% BY WEIGHT OF THEWRITING COMPOSITION, A CARRIER COMPRISING A TAR-LIKE SUBSTANCE SELECTEDFROM THE GROUP CONSISTING OF TAR DERIVED FROM PETROLEUM AND BITUMINUOUSDISTILLATE RESIDUE AND ASPHALT DISSOLVED IN A PETROLEUM THINNER AND OIL,SAID COLLOIDAL DISPERSION BEING FROM 60% TO 80% BY VOLUME OF THE WRITINGCOMPOSITION AND SAID CARRIER BEING FROM 20% TO 40% BY VOLUME OF SAIDWRITING COMPOSITION TO AND SAID TAR-LIKE SUBSTANCE BEING FROM ABOUT 16%TO 32% BY VOLUME OF SAID WRITING COMPOSITION, AND ADDING TO SAIDCOMPOSITION FROM ABOUT 5% TO 30% BY VOLUME OF A REFINED PARAFFIN BASENON-DETERGENT TYPE MINERAL OIL WHEREBY THE WRITING COMPOSITION CAN BECONTROLLED BETWEEN ONE WHICH REMAINS SUBSTANTIALLY ON THE SURFACE AND ISRELATIVELY ERASABLE AND ONE WHICH PENETRATES THE SURFACE AND ISRELATIVELY UNERASABLE